Not sure of the years but pre 1973 as they both have steel dashes. They both have 237 maxidyne engines. The blue DM600 has a 6 speed and the DM800 has what I believe to be a quadruplex. Both trucks ran very good when parked but have been sitting for several years. The DM600 has a jake brake but the DM800 does not. 6 is a triaxle and the 8 is a tandem with obviously very heavy rears. Probably 58,000 pounds or more. 12.00x24 rubber and Mack axles on camelback suspensions. Both trucks are pretty rotten and too far gone for any kind of restoration (in my opinion), however the engines, transmissions and drivelines are all good parts. They are essentially good complete parts trucks. Looking to get scrap price or maybe a little better if possible. Just trying to save them from the torch if somebody can use them. Located in the Pittsburgh, PA area. Please do not ask if I will export these or deliver them to a port. I will not deal with exporters. Thank you.